# -*- coding:utf-8 -*-
class Solution:
    def __init__(self):
        self.stack = []  
        
    def push(self, node):
        # write code here
        self.stack.append(node)

    def pop(self):
        # write code here
        self.stack.pop()
    def top(self):
        # write code here
        return (self.stack[-1])
    def min(self):
        # write code here
        return(min(self.stack))